QT9701B Datasheet, PDF (5/28 Pages) Quantum Research Group – CHARGE - TRANSFER CAPACITANCE SENSOR IC

1RWH WKDW WKH 47% IRUFHV WKH ;)5 OLQH KLJK DQG FODPSV VXSHULPSRVH D VHYHUH WUDQVLHQW RQ WKH VLJQDO DW WKH H[DFW
WKH &65 OLQH ORZ EHWZHHQ EXUVWV WR VHOIFODPS DQG GLVVLSDWH
(6' FXUUHQWV KRZHYHU ZKHQ SRZHU LV UHPRYHG WKLV IHDWXUH
REYLRXVO\ FHDVHV
! B7>AC 28A2D8C 34C42C8>=
7KH 47% LQFRUSRUDWHV D FLUFXLW RQ &+* ZKLFK FDQ VHQVH
VKRUWV WR JURXQG :KHQ D VKRUW LV GHWHFWHG WKH 287 DQG
PRPHQW ZKHUH LW VKRXOG EH VWDEOH
  6(1625 5(62/87,21
7KH VHQVRU¶V RYHUDOO VHQVLWLYLW\ LV D IXQFWLRQ RI VHYHUDO IDFWRUV
LQFOXGLQJ
67$7 OLQHV DUH IRUFHG KLJK IRU WKH GXUDWLRQ RI WKH VKRUW 6KRUW
GHWHFWLRQ RSHUDWHV E\ PRQLWRULQJ RXWSXW FXUUHQW WKURXJK WKH
LQWHUQDO SPRVIHW GHYLFH H[WHUQDO (6' FLUFXLWV WKDW LQFOXGH D
VHULHV UHVLVWDQFH FDQ OLPLW WKLV FXUUHQW DUWLILFLDOO\ WKXV UHQGHULQJ
WKH VKRUW GHWHFWLRQ V\VWHP LQHIIHFWLYH 2SHUDWLRQ RI WKH VKRUW
GHWHFWLRQ FLUFXLW LV QRW JXDUDQWHHG XQGHU DOO FRQGLWLRQV DQG
 7RWDO VDPSOHU FDSDFLWDQFH &V &]  &] &W
 %XUVW OHQJWK 1
 7RWDO DPSOLILHU JDLQ $Y
 $'& UHVROXWLRQ ELWV Q
 3RZHU VXSSO\ YROWDJH 9V
VKRXOG QRW EH UHOLHG XSRQ DV D SULPDU\ HOHFWURGH IDLOXUH _{'LIIHUHQWLDO JDLQ DW WKH RXWSXW RI WKH RSHUDWLRQDO DPSOLILHU LV}
GHWHFWLRQ V\VWHP $OVR QRWH WKDW WKH FLUFXLW FDQQRW GHWHUPLQH _{GHWHUPLQHG E\}
RSHQ HOHFWURGH FRQGLWLRQV
! ! ?>F4A BD??;H 0=3 ?21 ;0H>DC
7KH ,& UHTXLUHV D VWDEOH QRLVHIUHH SRZHU VXSSO\ $ ORZ FRVW
/ FODVV UHJXODWRU ZLOO ZRUN ILQH IRU YLUWXDOO\ DOO DSSOLFDWLRQV
EXW LW VKRXOG QRW EH VKDUHG ZLWK GHYLFHV WKDW FDQ SURGXFH
1 9V $₉
>@
&₇
^YROWV  &[`
7KH $'& UHVROXWLRQ LV GHILQHG LQ WHUPV RI YROWV SHU OHYHO
UHVXOWLQJ LQ WKH IROORZLQJ RYHUDOO VHQVLWLYLW\ HTXDWLRQ
WUDQVLHQWV RU HUUDWLF ORDGLQJ 'HVLJQV VKRXOG XVH D UHJXODWRU
VSHFLILFDOO\ IRU WKH 47% LI SRVVLEOH WHVWLQJ FDQ GHWHUPLQH LI
$'& UHVROXWLRQ
>@ 6HQVLWLYLW\ <sub>GLIIHUHQWLDO JDLQ</sub>
WKH UHJXODWRU PLJKW EH VKDUHG ZLWK RWKHU FLUFXLWU\
9<sub>6</sub>  <sup>Q</sup> 
7KH / VKRXOG EH SURSHUO\ E\SDVVHG RQ LWV LQSXW DQG
RXWSXW ,WV LQSXW VXSSO\ VKRXOG DOVR EH UHODWLYHO\ VWDEOH DQG
QRLVHIUHH VR DV WR PLQLPL]H IHHGWKURXJK QRLVH FRPSRQHQWV YLD
LWV SDVV WUDQVLVWRU $  —) WDQWDOXP RU  —) ORZ= DOXPLQXP
1 9<sub>6</sub> $<sub>9</sub>  &<sub>7</sub>
&<sub>7</sub>
1 $<sub>9</sub> <sup>Q</sup> 
^&[ SHU $'& OHYHO`
FDSDFLWRU LV UHFRPPHQGHG RQ WKH RXWSXW RI WKH /
$ JURXQG RU SRXUHG FRSSHU SODQH LV KLJKO\ UHFRPPHQGHG ^*LYHQ
2WKHU FLUFXLWV LQFOXGLQJ DQ\ RXWSXW GULYHU WUDQVLVWRUV VKRXOG
&W
1
 —)  [  —)
 $Y  Q  ELWV
 —)
QRW DOORZ WKHLU FXUUHQWV WR IORZ WKURXJK WKH VHQVRU¶V FLUFXLW DUHD
JURXQGV VKRXOG DOZD\V EH OHG EDFN WR D FRPPRQ WLH SRLQW DW
WKH SRLQW QHDU WKH HQWU\ RI WKH VXSSO\ RQWR WKH 3&% LQ
DFFRUGDQFH ZLWK FXVWRPDU\ ³VHQVLWLYH DQDORJ´ SUDFWLFH
7KHQ WKH RYHUDOO VHQVLWLYLW\ LV DERXW  IHPWRIDUDGV SHU $'&
OHYHO 7KLV FDQ HDVLO\ EH DGMXVWHG E\ DOWHULQJ DQ\ RI WKUHH
SDUDPHWHUV 1 ZKLFK FDQ EH DOWHUHG LQ WKH H^SURP VHWXSV
DPS JDLQ $Y DQG WRWDO VDPSOHU FDSDFLWDQFH &W
6HQVH OHDG FODPS GLRGHV VKRXOG VKXQW (6' FXUUHQWV EDFN WR
HDUWK YLD WKH PRVW GLUHFW URXWH SRVVLEOH ZLWKRXW WUDYHUVLQJ WKH
DUHD RI WKH FLUFXLWU\ (6' UHWXUQ FXUUHQWV VKRXOG DOVR QRW VKDUH
D FRPPRQ JURXQG SDWK ZLWK WKH VHQVRU FLUFXLWU\ 7KHVH FODPS
GLRGHV VKRXOG VKXQW DV GLUHFWO\ WR D ERDUG PRXQWLQJ KROH RU
RWKHU PDMRU JURXQG WLH SRLQW DV SRVVLEOH 3RVLWLYH FODPSHG
1RWH WKDW VXSSO\ YROWDJH 9V FRQYHQLHQWO\ GURSV RXW RI WKH
HTXDWLRQ  WKXV WKH VHQVRU LV ODUJHO\ LPPXQH WR VORZ FKDQJHV
LQ VXSSO\ YROWDJH DOWKRXJK LW FDQ EH VHQVLWLYH WR WUDQVLHQW
VXSSO\ H[FXUVLRQV ZKLFK GR QRW HTXDOO\ DIIHFW DOO DVSHFWV RI WKH
DFTXLVLWLRQ SURFHVV
(6' FXUUHQWV DUH RIWHQ QHJOHFWHG LQ GHVLJQV WKH\ VKRXOG EH
VKXQWHG YLD D KLJK TXDOLW\ ORZ LQGXFWDQFH E\SDVV FDSDFLWRU
DQGRU ]HQHU EDFN WR WKH VDPH JURXQG WLH SRLQW
&RPSRQHQW ORFDWLRQ LV UHODWLYHO\ XQLPSRUWDQW DQG QRQFULWLFDO
ZLWK WKH DERYH QRWHG H[FHSWLRQV DQG WKH FLUFXLW FDQ HDVLO\ EH
LPSOHPHQWHG RQ D OD\HU 3&%
  23(5$7,21$/ 02'(6
# 16 16>19 0=3 >19 <>34B
7KH 47% RSHUDWHV LQ HLWKHU RI WZR SULPDU\ FDOLEUDWLRQ
PRGHV
! " 0=0;>6 >DC?DC* B<? ;8=4
$Q DQDORJ RXWSXW PD\ RSWLRQDOO\ EH REWDLQHG XVLQJ D VDPSOH
DQG KROG FLUFXLW )LJXUH   7KH 47% SURYLGHV D VDPSOH
SXOVH 603 ZKLFK LV D SRVLWLYHGULYH SXOVH WLPHG WR FRLQFLGH
ZLWK D VWDEOH SRUWLRQ RI WKH RXWSXW RI WKH VLJQDO DPSOLILHU FKDLQ
7KH VDPSOH DQG KROG FDQ EH PDGH RI D +& W\SH VZLWFK
DQG D Q) FHUDPLF FDSDFLWRU IROORZHG E\ D &026 EXIIHU
DPSOLILHU
 µ1RUPDO¶ PRGH VHQVRU PDNHV XVH RI WKH VHWWLQJ RI
'HWHFW 7KUHVKROG 7KLV PRGH LV WKH IDFWRU\ GHIDXOW
VHWWLQJ (YRNLQJ %* LQ µQRUPDO¶ PRGH VLPSO\ FDXVHV D
UHFDOLEUDWLRQ WR RFFXU WKDW LV WKH UHIHUHQFH SRLQW LV
UHFHQWHUHG DQG ZLWK LW WKH WKUHVKROG OHYHO V  µ1RUPDO¶
PRGH LV %* PRGH DQG LV UHIHUUHG WR DV %* PRGH
WKURXJKRXW
 µ/HDUQ¶ PRGH 7KH VHQVRU LJQRUHV 'HWHFW 7KUHVKROG DQG
µOHDUQV E\ H[DPSOH¶ 7KHUH DUH WZR YDULDWLRQV RI µ/HDUQ¶
:KHQ XVLQJ D 6+ FLUFXLW WR REWDLQ DQ DQDORJ RXWSXW DYRLG
PRGH %*2%- DQG 2%-
XVLQJ D TXDG RSDPS LQVWHDG RI WZR VHSDUDWH GXDO SDFNDJHV
7KH VOHZ UDWH DQG ORDGLQJ RI WKH 6+ EXIIHU FDQ SURGXFH PDMRU
GLVWXUEDQFHV LQ RWKHU RSDPSV RQ WKH VDPH GLH
6ZLWFKLQJ PRGHV 7KHVH PRGHV FDQ EH HQWHUHG LQWR DW ZLOO E\
WKH XVH RI WKH %* DQG 2%- FRQWURO OLQHV DV H[SODLQHG EHORZ
7KH 603 OLQH VKRXOG QHYHU EH URXWHG QHDU WKH &V VDPSOH FDS
RU WKH DPSOLILHU RSDPS FKDLQ DV WKLV SXOVH FDQ HDVLO\
0DNLQJ WKH PRGH SHUPDQHQW 7KH VHOHFWHG %* %*2%- RU
2%- PRGH FDQ EH VWRUHG ³SHUPDQHQWO\´ LQWR WKH H[WHUQDO